Electrophotographic imaging devices and their operation are generally well known in the art. Conventional electrophotographic imaging devices include a photoconductive surface that is often supported on the exterior of a rotatable, cylindrical drum. The typical electrophotographic imaging device also includes a light source. The photoconductive surface is configured to be moved past the light source during production of an image.
The light source can be in the form of a laser, or a series of light-emitting diodes, or the like. In any case, the light source is configured to be directed at the photoconductive surface and across the width thereof as the photoconductive surface is moved past the light source. The light source is also typically configured to be selectively pulsed as it is directed at the moving photoconductive surface.
Such pulsing of the light source while it is directed at the moving photoconductive surface allows a two-dimensional latent image to be produced on the photoconductive surface. The image is xe2x80x9clatentxe2x80x9d in that it is defined primarily only by a difference in the electrical charge of specific areas of the photoconductive surface. That is, the electrical charge of the areas of the photoconductive surface that make up the xe2x80x9cimagexe2x80x9d is typically substantially different from the electrical charge of the areas that do not make up the image.
In addition to the light source and the photoconductive surface, conventional electrophotographic imaging devices also typically include a developing system. The developing system is configured to apply toner to the latent image on the photoconductive surface so as to xe2x80x9cdevelopxe2x80x9d the latent image into a visual image. After the image is developed on the photoconductive surface, it is ultimately transferred to a final image carrier, or medium, such as a sheet of paper.
The developing system often includes a toner reservoir, or storage container, as well as a toner metering/distribution mechanism. The toner metering/distribution mechanism is configured to draw toner from the toner reservoir and apply or distribute the toner onto the photoconductive surface in order to develop the latent image into a visual image. The toner generally has an associated electrical charge so that, when the toner is applied to the latent image on the photoconductive surface, the toner adheres to the portions of the surface which make up the latent image, and does not adhere to the remainder of the surface.
The toner reservoir and the toner metering/distribution mechanism are often incorporated into a toner xe2x80x9ccartridgexe2x80x9d that can be conveniently removed and/or installed into the imaging device. The xe2x80x9ccartridgexe2x80x9d configuration of the toner reservoir and toner metering/distribution mechanism is beneficial in that replenishment of toner requires only that the empty toner cartridge be removed from the imaging device followed by the installation of a full toner cartridge.
Typically, conventional toner metering/distribution mechanisms include some type of stirring device that is configured to stir or physically agitate the toner stored within the toner reservoir. Such stirring and/or agitation of the toner generally aids in distribution of the toner. However, prolonged stirring of the toner can have deleterious effects on the toner charge. For example, prolonged stirring of the toner by a stirring device within the toner reservoir can cause a significant loss of toner charge. Such a loss of toner charge can result in poor performance of the toner and/or degraded image quality.
In accordance with one embodiment of the present invention, a toner cartridge includes a body that defines a primary toner reservoir and a secondary toner reservoir. The toner cartridge also includes a gate device that is operatively supported, at least in part, by the body, and that is configured to selectively release toner from the secondary toner reservoir and into the primary toner reservoir. Additional secondary toner reservoirs can be included, wherein a plurality of secondary toner reservoirs are configured to each release toner into the primary toner reservoir by way of respective associated gate devices. The toner cartridge can also include an activation mechanism that is configured to open and/or close the gate device.
In accordance with another embodiment of the present invention, a method of operating a toner cartridge includes providing a toner cartridge that defines a primary toner reservoir and a secondary toner reservoir. The method also includes placing a primary quantity of toner in the primary toner reservoir, and placing a secondary quantity of toner in the secondary toner reservoir. The toner cartridge can be operated to deplete the primary quantity of toner from the primary toner reservoir. The secondary quantity of toner can be automatically dumped from the secondary reservoir into the primary toner reservoir.